The invention relates to architectures of feed holes for fluid ejection devices and a method of manufacturing the same.
Printheads for ink jet printers include components that cooperate with an integrated ink reservoir to deliver ink to an ink ejection device. As printheads deliver higher print resolutions, there is a desire to form printhead structures to direct ink flow from the reservoir or fluid supply through the printhead while preventing debris from entering the firing chambers or contaminating the ink.
Debris that may pass through printhead structures is often trapped by narrow feed channels, thereby inhibiting ink flow. Filters may be incorporated into the printhead to trap debris before it blocks ink flow and affects the print quality. Adding separate filters to printheads, however, increases the number of manufacturing steps required to make a printhead. Further, thin film filters tend to fail during the manufacturing process because there is not enough material to strengthen and support the filter structure.
There is a desire for a particle tolerant ink jet printhead structure that can be reliably manufactured.
There is also a desire for a manufacturing method that can define a particle tolerant architecture for ink jets while maintaining structural strength and stability.
Accordingly, an embodiment of the present invention is directed to a fluid ejection device comprising a substrate having a fluid slot defined from a first surface through to a second opposite surface, an ejection element formed over the first surface and that ejects fluid therefrom, and a filter having feed holes positioned over the fluid slot near the first surface, wherein fluid moves from the second surface through the feed holes to the ejection element, wherein the filter is formed of a first material that is surrounded by a second material.
Another embodiment of the invention is directed to a method of manufacturing a fluid ejection device comprising applying a mesh pattern over a back side of a substrate opposite a circuit side, wherein the mesh pattern defines at least two apertures therein, and wherein the mesh pattern is substantially more resistant to an etchant than the substrate material, and etching the substrate and the mesh pattern with an etchant from the back side to form a slot from the back side to the circuit side of the substrate, and to form a plurality of filters in the slot and adjacent the circuit side of the substrate that corresponds to the at least two apertures in the mesh pattern.
A further embodiment of the invention is directed to a method of manufacturing a fluid ejection device comprising applying a mesh pattern over a front side of a substrate opposite a back side, wherein the mesh pattern defines at least two apertures therein, and wherein the mesh pattern is substantially more resistant to an etchant than the substrate material, and DRIE etching the substrate and the mesh pattern with an etchant from the front side to form a trench partially through the substrate in each of the at least two apertures of the mesh pattern, wherein a wall is formed in between each of the adjacent trenches, and isotropically etching the wall formed in between each of the adjacent trenches to form one large trench in the substrate bordered on one side by the mesh pattern.
Another embodiment of the invention is directed to a method of manufacturing a fluid ejection device comprising forming depressions in a first side of a substrate, depositing in the depressions a first material surrounded by a second material to form an etch stop in each of the depressions, and etching the substrate with an etchant to form a fluid slot through the substrate, wherein each of the depressions form part of a particle tolerant architecture within the fluid slot.
Further aspects of the invention will be apparent after reviewing the detailed description below and the corresponding drawings.